Hexagram 11 is Earth over Heaven, and the arrangement looks wrong until the logic is stated, at which point it becomes one of the most elegant things in the book.
Heaven's tendency is to rise; Earth's is to sink. Put Heaven underneath and Earth on top and the two are moving towards each other. They meet, interpenetrate and exchange, and the result is called Peace, or Prosperity, or Advance depending on the translation. Put them the conventional way up, Heaven above and Earth below, and each moves away from the other; nothing meets; and the resulting hexagram, number 12, is Standstill or Obstruction.
The two figures are exact inversions and they sit side by side in the King Wen sequence, which is the clearest single demonstration that the sequence is structured rather than arbitrary. Whatever else King Wen's order is, it is not random, and pairs of this kind run through it from beginning to end.
The reading of hexagram 11 is favourable and unusually unqualified: a period in which things connect, communication works, and the small departs while the great approaches. The caution is in the lines rather than the judgement. The third warns that no plain is without a slope and no going without a return, and the top line has the city wall falling back into the moat. Peace in this book is a phase, not an achievement, and the text says so at both ends of the figure.
The trigram logic just described is itself a product of the Ten Wings rather than of the oldest layer. The core text gives judgements and line statements; the reading of hexagrams as two stacked trigrams with characteristic motions is a commentarial system, and a very good one, laid over material that predates it.